The plan was eventually headed off by the US, in particular by then-Defense Secretary Dick Cheney, who later became a key architect of the 2003 Iraq War.

The ‘Iron Lady’ reportedly told then-US President George Bush Sr that faced with Saddam’s aggression it was “no time to go wobbly” as the Western powers postured for a war with Iraq.

Records show that in a meeting in October 1990, amid fears that Saddam could use chemical weapons himself, Thatcher told Cheney: “We had to decide what our response would be. If we wished to deter a CW [chemical weapons] attack by threatening to retaliate in like manner, we must have CW weapons [sic] available.”

Cheney responded that Bush had a “particular aversion to chemical weapons” and was disposed towards a “massive conventional response to a CW attack” rather than a like-for-like WMD battle.

The exchanges, which were not included in Thatcher’s memoirs, show that her threat at the time to use nuclear weapons was a bluff.

Cheney asked if she “could contemplate the use of nuclear weapons in a Gulf conflict.”

“The prime minister said she would be most reluctant to consider this, indeed she would rule it out, although nuclear weapons were always there as the ultimate deterrent.”

Strikingly, as with Labour PM Tony Blair over a decade later, Thatcher would try and keep her own cabinet out of the loop about the coming war.

In one memo she wrote: “The fewer the people who know, the better. We have bad experience of secret papers leaking.”